Mike's Musings #6: FSX Disaster Recovery - Part 1

By Mike McCarthy (6 February 2007)

Summary

By the way, if you don't want to read my vanity writing, search for the word "ahem" and begin reading the technical material there. This use of "ahem" will be another new policy in addition to the new Summary/Conclusion policy.

Testing ... Testing ... (tap tap tap) ... Is this thing on?

I was expecting a lot of feedback regarding my FSX article series, but that's fine. I write mainly for an audience of one, two if you count webmaster Nels Anderson, who is forced to read every word I write in order to edit my pieces for posting.

The audience of one is a girlfriend of my early teenage years who reads my stuff while she takes sunset walks on the beaches of the Pacific and Atlantic oceans. She wants to remain anonymous so I will refer to her simply as "RGB", not her real initials.

RGB owns beachfront property on both coasts of the USA. She winters somewhere on the Southern California seashore and she spends her summers somewhere on the Massachusetts seashore. She does not have to work. Given her wealth and her looks, why didn't I marry RGB? Well, RGB certainly had been Miss Right, but then her parents placed her in a boarding school out-of-state, and EHM was Miss Right Now. EHM and I became joined at the lip when we were sixteen, and we are still married. No amount of money could possibly substitute for this.

Anyway, in the past year I've sent RGB thirty or so articles on various subjects and of varying lengths. Edited versions of some of that material will find their way onto my upcoming writing web site in the form of "Letters to RGB", an approach she has agreed to.

RGB doesn't like to judge anybody else's creative undertakings. Like you folks, she never tells me which of my articles she did or didn't enjoy, though she assures me that she reads everything I send to her, and that she likes reading my stuff. She also never comments on my photography, though she likes it when I send her good photos. (Without her getting specific she did once say that I have a good eye.) She doesn't even comment on the various artists' web sites that I call her attention to, even though she herself was a Fine Arts major, and even though she herself is a painter.

To force the issue, for Christmas I sent RGB a beautiful indestructible bookmark, an uncirculated new-style twenty dollar bill that I had laminated myself using very thick lamination material. At last! She finally complimented me by saying "the lamination job was superb". She also remarked that it was a very Andy Warhol kind of thing for me to have done, exactly the reaction I was hoping for.

I had originally planned to refer to RGB as "Barbsie", but she objected in the strongest terms because it reminded her of "Barbie Doll", a cultural icon which she detests. Thus we have "RGB" instead. Barbsie is another old flame, the beautiful 13-year-old subject of the very first roll of film I ever developed. Barbsie will never read what I'm writing here so I feel comfortable using her actual nickname. However (and I know I'm not supposed to begin sentences with "however", but the language is and always has been changing, and as proof I will cite the fact that we no longer speak proper Elizabethan English), if Barbsie does happen to come across this article she will learn that I carried one of those photos in my wallet for ten years until it burned up in an office fire. She will feel flattered, don't you Babs.

So ... Being given the silent treatment means nothing to me because my Celtic Writing Genes are in control. Even if you're not reading, I have no plans to stop writing. In fact, in the immortal words of Arlo Guthrie in Alice's Restaurant, "I've been singing this song for twenty five minutes now. I could sing it for another twenty five minutes. I'm not proud ... or tired".

(And yes, I know that the period belongs before the closing quotation mark, but the language is changing as discussed above. And yes, I know that sentences should not begin with "and" or "but", and I know that "so" is not a sentence. But good grammar has always been whatever educated people say it is. Furthermore, as Winston Churchill once observed on the subject of split infinitives, strict insistence on perfect grammar inevitably leads to ludicrous constructs such as "that is a situation up with which I would rather not put".)

As in Mike's Musings #4, again I have something important to say. Again I will illustrate the importance of the technical discussion to come with lyrics from Mark Griffin's copyrighted hip-hop number "Truth Is Out Of Style". With my taking editorial license, we have ...

"Thank you, MC Griffin" is the first thing that you'll say as you are
Jumping out of bed at the start of every day. You will be
Dropping to your knees while you are calling out my name, saying
"Thank you, thank you, thank you". You'll revere the day I came

Into your life. I'll now reveal the secret of my own success, so from
Now on you can share in my continued happiness.
You will know the blissful peace of all the masters Zen of old,
And everything you touch will turn to fourteen karat gold.

Oh my. Don't be distracted by the rhyming doggerel form of this cynical poetry. I can edit lyrics for meter as I did here, but I could never have written the lyrics. I can't write songs but I can do arrangements because I have "golden ears". I can't write songs but I can fix them up because I'm a "song doctor". I can't write songs ...

... But I can write Limericks! In fact, I think I'll toss one off right now ...

There once was a flight simulator,
a/k/a the "Fright Stimulator".
Its 0-0 conditions
Roused my inhibitions,
Delighting the program's creator.

Want more? Of course you do ...

A product known as "FSX",
Does old and new flight simmers vex.
Its too-awful stutters
Cause flight simmer mutters.
On Microsoft we wish a hex! (Just kidding, Microsoft.)

How about this one? ...

On ex-tended final approach,
FO offers a long smoking [censored].
I decline. (Very sadly,
T'would make me fall madly
In love with the FA in Coach.)

As you can see, Limericks come easily to me. Here's one to RGB, in French, which was her first language. (She says that I write in "Francais Torque ", Twisted French.) Oops, I can't find the original, so now I'll have to try to recreate it ...

La reine Francaise nom de Marie
Antoinette avait dans Belle Paris
Une palais si grande que
Le Peuple demande ce
Mais "Let them eat cake" elle a dit.

Limericks in French being a Crime Against Nature, I must throw myself upon the mercies of L'Academie Francaise. I must also offer my deepest apologies to Pierre Guenette in Montreal, to all other French-speaking people of the world, and to all students of the French Revolution. A loose translation ... The French queen Marie Antoinette had, in the beautiful city of Paris, a palace so opulent that The People demanded to take it over. Unfortunately, the queen instead told The People to [censored].

I thought I was finished writing about FSX, at least for now, but no-o-o-o-o, I ran into problems, and you need to learn about both the problems and the recovery strategy. Let me say at the outset that in conjunction with a reinstall of FSX I was able to use System Restore to completely recover from the disaster described in this article. Let me also say that it took an eighteen-hour day of floundering for me to get to the point where I decided that System Restore would be needed and would work.

Eighteen hours sounds like a long time. However, this wasn't so bad considering that the alternative would have been for me to make a complete new set of backup CDs, then to zero my office computer's hard drive, then to reinstall everything that normally lives on my office computer and, finally, to reinstall FSX along with its older brother FS2004. For business reasons I could not have afforded the downtime because I need the machine for daily office-type work.

In all, that whole process would have taken me perhaps three eighteen-hour days, if everything was to be tweaked up exactly the way it had been. It was instead much easier to use System Restore so that I could simply work one of my ordinary programmer nine to five days. (Nine AM to five AM.)

I learned this lesson the hard way. Without going into the reasons why I felt that I needed to do it, I uninstalled both FSX and FS2004. This made the various FS-related file system folders vanish, taking their name-sorted state with them. I then consolidated the hard drive free space. After that, before doing a new alphanumeric sort, I reinstalled FS2004, and then I reinstalled and reactivated FSX. (Third activation on the same machine in a matter of days. To my surprise, no hassles.)

Unfortunately, it was after the reinstallation of FSX that real problems began. (See? If it ain't broke, don't fix it.)

Evidently the registry entries for FSX had somehow become corrupted during the reinstall, thus yet another reinstall would not have helped. Fortunately, as will be discussed in FSX Disaster Recovery Part 2, when I rolled back to an earlier, healthy time via System Restore, my registry also got rolled back to a healthy state. This was no accident - - it was precisely the effect I was trying to achieve, and I was able to do it because I had made preparations for disaster beforehand. You can do it too. I'll be showing you how.

So ... I'll now try to explain in simple English what System Restore is and how it works. As with Musings #4 this is going to be difficult for me because I'm a typical computer nerd. I tend to assume that as long as I understand what I'm saying, everybody else will too. I'll try to be clear but I would like you folks to email me regarding whether I'm succeeding in my goal of providing easily understood layman's explanations of computer technical matters, okay?

If the goal is being met, I'll continue to take these kinds of approaches in future articles. Computer professionals will recognize that I'm oversimplifying and that not everything I say here is the literal truth. However, the oversimplified System Restore described here does in fact produce the same effects as does the real one, and it's much easier to understand.

Now pay attention, 007 ...

Let's also say that you are going to modify the house, adding an exterior deck and ripping out one of the bathrooms. Let's further say that both activities will be going on at the same time. (In my home state of Colorado, like every other construction contractor you will hire two crews of undocumented workers to accomplish this. The workers don't speak English, they speak only TechnoBabble, but at least these workers, the XP file system, will work for free.)

Now ... Because you actually have a construction project going on, to make their future job of reconstruction possible, the insurance company demands a complete history of the changes you make to your house. In fact, they want a history logbook complete with entries like "On Tuesday, at 5:07 PM, a plank was added to the deck under construction. The plank looked like this [detailed companion photograph]." We'll call this kind of logbook entry an "Add".

Another kind of logbook entry would be "On Monday morning, at 9:24 AM, as part of the bathroom demolition we ripped out the sink faucet, which looked like this [photograph]." We'll call this a "Delete".

The third kind of logbook entry would be "On Friday we repainted one of the deck planks. It now looks like this [photo]". This, of course, is a Change.

Do you see where we're headed? If you maintain a complete time-stamped log containing each and every Add, Delete and Change, along with the companion photos, then at any time the insurance company will be able to reconstruct the house by taking the original as-built drawings and applying the logged, time-stamped activities and photos to those drawings in the exact order given in the logbook.

The current state of the project would change as the bathroom demolition and the deck construction and repainting proceeded, but that wouldn't matter provided that the logbook were being kept completely up to date as each Add/Delete/Change step was being taken.

Ignoring my oversimplifications, this is exactly how System Restore works. It monitors your folder and file adds, deletes and changes, maintaining the resulting time-stamped file system activity history in a special database in the root of your C drive. This database is contained in a file named "System Volume Information", entirely equivalent to the time-stamped activity logbook. The "photos" are compressed versions of the contents of the various files involved in the adds, deletes and changes. These are inserted into System Volume Information as part of the relevant logbook entries.

The only additional concept we need is that of "restore points". These can be thought of as labeled sticky notes applied to particular pages of the log. (I should have mentioned that each logbook page contains only a single entry, i.e. a single add, delete or change.) To put the system back the way it was when a given restore point was created, all the insurance company has to do is to start from the as-builts and then apply the logged activities up to and including the logbook page to which the sticky note was applied. (Note that logbook pages more recent than the sticky note will continue to exist, but they will have been ignored for purposes of accomplishing the restore in question.)

The logbook can be thought of as a loose-leaf binder containing a fixed number of pages. The capacity of the loose-leaf binder is a function of your hard drive size, the amount of space devoted to System Volume Information typically being around 10% of drive capacity.

New entries are made at the front of the book, so the log is maintained in reverse chronological order. Because the book can hold only a fixed number of pages, to add a page (newest) at the front of the book you must discard the page (oldest) at the back of the book. This means that over time portions of restore points, or even whole restore points, will be crowded out of the back of the logbook by the new entries being made at the front. The implication here is that there is a limited period of time during which a given restore point can in fact be restored successfully. After that period the necessary set of logbook pages will be either incomplete or entirely absent.

Now for a more difficult concept, one relating to System Restore efficiency. Even ignoring the fact that logbook pages get crowded out, it would be tremendously time-consuming to go all the way back to the original as-builts each time a restore is to be accomplished. What System Restore does instead is this ...

When you create a restore point you are implicitly saying "Let's make a new set of as-builts drawings, ones which document the state of the house as it exists right now." The new as-builts will be placed at the front of the logbook with a sticky note behind them. Naming this restore point "B", we now realize that there must be in existence a comparable set of as-builts for the earlier restore point whose name is A. To accomplish a restore to state B, we take the A as-builts and apply all of the subsequently-logged activities up to the B sticky note, i.e. up to the moment in time when the B as-builts were created. And so on for restore points C (which will be based on the B as-builts), D (which will be based on the C as-builts), etc.

Mike McCarthy
xxmikexx@qwest.net

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Addenda ...

In Musings #4 I forgot to mention two things: First, if you do adopt my alphanumeric folder/file name sort strategy you will have to repeat the procedure periodically because the name-sorted file system organization will degrade over time. Second, if you try O&OD but then decide not to buy it, it's perfectly okay to revert to using the built-in XP defragger or other reliable equivalent, including the faster and more effective freeware program "Power Defragmenter", downloadable from several different sites. (Just Google the name of the utility.) Note that to my knowledge Power Defragmenter will not defrag PageFile.sys or any of the other special system files of interest that O&OD treats, and treats properly. Note also that neither the XP defragmenter, PowerDefragmenter nor Page Defrag can do alphanumeric sorts.

Errata ...

In Musings #4 I asserted that it would be years before fast, affordable 16 GB flash drives became available. The good news is that SanDisk recently announced a photography 16 GB flash drive with a read transfer rate of 20 MB/sec. The bad news is that the chip costs more than $1,000 US, is for cameras only (I think), and anyway 20 MB/sec is not nearly fast enough for our FSX needs. Still, the desired devices may not be so far out in time after all.

As a reader pointed out to me, in Musings #3 I incorrectly attributed authorship of the song "Da Doo Run Run" to Bette Midler. Revisiting the issue via Google I saw that in actuality the writing credit for this song, and for many others, is shared by the song-writing trio of Ellie Greenwich, Jeff Barry and Phil Spector. It is they who wrote the girl group songs I referred to. By the way, it turns out that Spector also produced John Lennon's 1970 piece "Instant Karma". I would never have guessed that. Supposedly the song was written, arranged and recorded all on the same day. I would never have guessed that either. (The only comparable session I know of was the 1957 instrumental hit "Tequila", which was conceived, arranged and recorded in ten minutes flat. True, the published version of "It's My Party" is the first take of Leslie Gore singing, but it was preceded by an Atlantic Records house band rehearsal session, and anyway Quincy Jones had written the arrangement days earlier.)